


For Scientific Purposes

by Isabel_Nightfel



Category: Naruto
Genre: AU, Doggy Style, F/M, Hand Jobs, Honestly this is Terrible, How Do I Tag, I Tried, I Wrote This Instead of Sleeping, I was Winging It, Inuzuka's have canine traits, Kiba doesn't know what he's getting into, Kiba is Sweet During Aftercare, Knotting, Licking, Male Inuzuka's have a knot, Naked Cuddling, Nara Shikamaru (mentioned) - Freeform, Nara Tsuyuko (OC) is curious, Not Beta Read, S.O.S -Someone send me Mental Help, This has like Zero Flow, Vaginal Sex, Wants to play with a penis, Why Did I Write This?, akamaru is a good dog
Language: English
Status: Completed
Published: 2019-06-02
Updated: 2019-06-02
Packaged: 2020-04-06 13:13:29
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 1,973
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/19063411
Author URL: https://archiveofourown.org/users/Isabel_Nightfel/pseuds/Isabel_Nightfel
Summary: Nara Tsuyuko is a medic, meaning she's seen all parts of the human body, but she's still curious about a certain piece of male anatomy - the penis. Now if she could just convince someone to let her play with their's.





	For Scientific Purposes

**Author's Note:**

> Okay, so I honestly have no clue where this idea came from, but for some reason my brain has decided since Inuzuka's have more canine characteristics then male Inuzuka must have knots...so I just decided to run with it...I'm going to Hell for this. This is my first story on here also so, hopefully you enjoy. *sigh*

Tsuyuko was many things – a chunin, a medic, a Nara – but most of all she was curious, and her curiosity had brought her to where she is now. Sitting on Inuzuka Kiba's bed, playing with his penis as he grunted and growled, head thrown back in his pillows.  
Now dear readers, I'm sure you're wondering how we got to this moment, how about we look back and see.  
-x-x-x-  
A loud knock sounded through Kiba's small home. Once he became a jonin his mother finally decided to kick his ass out of the main house and told him it was time to find a mate and have some pups of his own. Needless to say he was a embarrassed and slightly annoyed, but hey it got him away from his mother's yelling and his sister's nagging.  
Anyway, Kiba pulled open the door and was greeted with the sight of a Nara – though not the one he was most used to seeing.  
“Hey Tsuyu, what are you doing here?” Sure Kiba knew Tsuyuko – better known as Tsuyu to her friends – they were friends but they didn't really hang out as much as he did with Shikamaru.  
“Kiba, I have a question. You can say no, but you were the one I decided was best to ask. Can I come in first?” Tsuyu was always a bit of a fast talker. She probably had to be the most un-Nara-ish Nara there was, calling her lazy would be completely untrue.  
Stepping away from the door Kiba motioned his fellow brunette into the home. Upon entering the Nara greeted Akamaru with a few scratched and pets, because he was the best boy ever she would say, then continued into the living room and took a seat of Kiba's couch.  
Kiba soon came to sit with her before asking, “So what's up?”  
“Well you see, I'm curious.”  
“And?” Because this was nothing new, Kiba was used to Tsuyu's weird questions. Though, none had been a weird as what was about to come out of the female's mouth.  
“Can I play with your penis?” Had Kiba been drinking anything he'd be chocking right now. As it was he nearly fell of the couch.  
“W-what did you just ask? I don't think I heard you correctly. Did you just asked to _play with my penis_?”  
“Yep, it's purely scientific mind you. I've seen them, in both anatomy book and real life, but I've never actually gotten the chance to mess with one. So, I decided the best way to kill my curiosity was to ask someone.” For some reason the comment about it being purely scientific kind of stung.  
“Why me?” The Inuzuka asked still not believing completely that she asked him that question.  
“Well I figured you were the one to most likely say yes. My other choice of Shikamaru but he's out of the village on a mission, so here I am. Plus, if you say yes, you get a free hand job out of it, so it's a win-win.”  
Kiba paused, she had a good point there, he'd been a bit sexually frustrated lately, who was he to say no to a hand job from a pretty female. _'I must be getting close to my rut to even be considering this.'_ Sighing, he stood from the couch.  
“Alright, but we're doing this in the bedroom, no on the couch.” And with that he made his way into his room not realizing what he was getting into and bring us back to the point in time at the beginning of the story.  
-x-x-x-  
Twisting her wrist and applying a little more pressure Tsuyu smirked as she watched the reaction of the penis in front of her – every twitch was fascinating. “Huh, so what I've read is pretty spot on. Steel wrapped in silk, it really does feel like that.”  
“Pretty sure...that ain't in...an anatomy book.” Kiba had to pause every few words to catch his breath. For never having done this before she was pretty good.  
“Yeah, we all have our vices, mines reading erotica. I just do it in private instead of public like Kakashi does.” Kiba wanted to reply but Tsuyu's hands did this thing and suddenly his train of thought was completely derailed and all he could do was moan. “Now this I've not come across in any _human_ anatomy book,” Tsuyu commented as she reached the base of Kiba's cock where a large fleshy bulb the size of a softball now sat. The Nara leaned in closer to get a better look while giving the bulb a good squeeze.  
“I-it's a-” Tsuyu cut Kiba off.  
“I know what it is. I just wasn't aware that it was possible for you to have a knot. I thought is was only a canine thing. Thought, I do suppose since the Inuzuka's share so many canine characteristics, this one isn't a far stretch.” Tsuyu giggled at her own pun. Now she was even more curious. _'I know it's function, but would it hurt to take this? Would it even fit? I-I really want to know.'_ The Nara took a peak at Kiba's face and smiled at the look of pure pleasure on it.  
“Kiba, new question.” He grunted to acknowledge what she said, Kami her hands felt amazing. “Will you show me how your knot works?” The Inuzuka's eyes shot open at the female's question. Leaning up on his elbows he cocked an eyebrow at her.  
“Let me just make sure we're on the same page, you want me to fuck you and knot you?” Tsuyu laughed and gave his cock a tug before letting go and standing.  
“Yep.” Kiba watched a she began shedding clothes as if it were a normal thing for the two of them to see each other bare. His eyes narrowed as he took in her form, from her narrow waist to her wide hips. The more feral part of him noted they would be perfect for giving birth. Now without the layers of clothing he could get a good whiff of her scent – she was wet and her hormones permeated the air. _'So this has been effecting her as much as it has me.'_  
Faster that she was used to Kiba reached forward and Tsuyu found herself face-down on the bed with her ass in the air and Kiba's nose shoved into her crotch. “W-what are you doing?”  
“Don't worry, I-I want to smell you – you smell amazing.” Kiba's reply made Tsuyu blush and then she was moaning. Kiba had decided smelling wasn't enough he wanted to taste her too. Flatening his tongue he gave long, strong licks from clit to puckered anus, pausing occasionally to take deep breaths of her quivering heat as more of her juices ran. He could feel her body tense as her mewls and moans became louder. With a final lick and a loud cry, Tsuyu's organism flowed through her, her pussy clenching around Kiba's tongue. The Inuzuka gave a few more gentle licks before he shifted so he was hovering over the female Nara's naked back.  
Tsuyu panted as she came down from her high, sure she'd had organisms before but a male tongue was different from her fingers and toys. He body jumped slightly as he felt Kiba lean down over her back – his strong chest was pressed flat to her. His mouth was right next to her ear and she would hear his breath come out in short pants.  
“Are you ready? I'll try and be a gentle as possible, but there's a good change my more feral side will take over.” Tsuyu could only nod, she figured with the canine features there might have been a more feral mindset somewhere, and he just confirmed her theory.  
Kiba leaned back and grabbed his aching hard-on before rubbing the tip between her lower lips. Pushing forward gently he was in and man was it bliss – her inner walls were hot, wet, and tight – he could already start to his hold on his more feral side slip, he just hoped he could have he fully adjusted before his hold slipped completely.  
Tsuyu gave groan of slight discomfort as Kiba pushed his thick cock into her pussy – it was bigger than any of her toys. After a few experimental thrusts for her to get used to the large intrusion Kiba's hips shot forward with a grunt and he was buried up to the hilt in her. Tsuyu moaned loudly but she was confused, what happened to the knot.  
“It goes down without active stimulation. I was letting it deflate the entire time I was preparing you.” The Inukuza explained as if reading the Nara's mind. “You're start to feel it once shortly. Ready?”  
Tsuyu's answer came in the form of her wiggling hips. With the green light Kiba went to work. His first few thrusts were slow and gentle but as his hold on the feral side of him slipped they became harder and rougher. After the first 10 or so Tsuyu could start to feel the difference in Kiba's shaft – every thrust that followed made her feel fuller and turned her into a panting, moaning mess as she pushed back meeting him halfway. Kiba's grip on her hips became tighter and his thrust almost became painful as his hip bones slapped against her ass cheeks. In and out his cock worked faster, each time it became harder to pull out as his knot continued to inflate. Tsuyu's body was tensing and her abdomen coiling as she came closer and closer to her peak.  
Grunt, moans and the sound of slapping flesh filled the room and as a haze of pheromones clouded Kiba's head. The now feral male curled himself over his mates back, he was so close, only a few more thrusts and he would successfully knot his female. She was very fertile, they would make strong pups.  
The Nara cried out Kiba's name as the male's thrust sent her over the edge, his knot slipping in a final time before becoming stuck. The feral Inuzuka howled as his female's clenching pussy around his knot sent him over his own edge, spaying her warm insides with hot semen. Several second of panting followed as Kiba started to regain full awareness, his forehead rested against Tsuyu's back, leaning forward he laid several kisses at the dip of her spine – he could still hear the female's soft moans.  
“Kiba...Kiba, so full. I've never felt so full.” Kiba's heart swelled with pride at the Nara's words. Shifting his arms, he wrapped them fully around Tsuyu's belly and reached down to feel where they were connected. He hushed her gently when she gave a whimper as he accidentally brushed her overstimulated clit.  
“Hook your arm around my neck. I'm gonna roll us onto our sides to take the pressure off your hips and knees. I'm fully seated so we're going to be like this for a while.” Once they were both on their sides Kiba began running his hands and lips over Tsuyu's skin. Gentle caresses to help take her mind off the softball size knot stuck in her pussy. The female Nara had to giggle as some of his caresses were light a feathers. After what felt like hours, or it could have been half-an-hour Kiba's knot started to go down, though not wanting to hurt Tsuyu he waited until it went down completely before removing his cock from her soft, warm pussy. She gave a whimper at the emptiness but rolled over and snuggled deeper into Kiba's chest. The silence stretched on for a while as the two continued to caress and lay gentle kisses on their partner's skin, until Kiba finally broke it when a though struck him.  
“We didn't use the Jutsu!”

**Author's Note:**

> Well there you have it...and it's crap. At some point I'll probably go in and do a full overhaul of it.As the tags say it's not beta read, and I suck pretty bad at grammar. Math was my strong suit in school, so don't grade too harshly Senpai. I mostly write for myself, but decided to share this one for some reason. Is she pregnant? I don't know, but probably yes.


End file.
